The coroner in Vancouver, British Columbia, has reported that the death of popular television actor Cory Monteith, at age 31, was caused by an overdose of heroin and alcohol. Directly or indirectly, Monteith would appear to have been a customer of the drug dealers, like Miguel Angel Trevino Morales, who so often indulge in brutal behavior to gain market superiority.

Morales, also known as Z-40, led what was believed to be the most feared and most violent drug cartel operating in Mexico, and that’s no minor distinction, given the history of cartel-sponsored atrocities.

But this week a unit of the Mexican Marines arrested him without incident, and thus finally one of the most ruthless cartel leaders found himself behind bars.

“He was a crazy, nasty, violent guy,” said Sylvia Longmire, a consultant who recently wrote “Cartel: The Coming Invasion of Mexico’s Drug Wars.” “If there was a choice, he always killed in the ugliest way possible.”

She was referring to Morales’ incomprehensible passion for boiling down the bodies of his enemies into a kind of stew after their bodies were dumped in vats of acid. After that, only sets of their stained teeth remained. But he also had a similar passion for dismemberment, beheadings and even public executions. Morales had an appetite for brutality, and in his warped mind, the bloodier the death of his foes, the better.

Even so, for Morales it wasn’t just blood and gore. He was in business. Big business. Helped by his brother, he had created an effective money-laundering scheme that involved the buying and selling of quarter horses in Texas and Oklahoma, transactions facilitated by the millions of dollars he earned in the drug trade.

The arrest of Morales was a huge achievement for Mexico’s president, Enrique Pena Nieto. He had campaigned partly on a pledge to adopt a new strategy to cripple the drug trade, an effort that had been begun by his predecessor, Felipe Calderon, but that was still a long way from success.

Reportedly, the arrest resulted from at least eight months of extremely detailed intelligence work and, according to some reports, the police had help from at least one informer who was close enough to Morales to know the details of his travel schedule.

For years, Americans have been appalled by the reports of brutal violence so often attributed to Mexico’s warring drug cartels. The competing gangs are absolutely merciless in their pursuit of market domination. And that brings us to this critical question: Exactly what is the market for their illicit products?

We all know the answer, don’t we? In a large way, and for many years now, the prime market has been the United States. If the American appetite for illegal drugs wasn’t so huge and so enduring, the profits from drug trafficking would diminish in a big way. Their neighbors to the north are simply the easiest market for the cartels to reach, even if they risk capture by vigilant border guards and the United States Coast Guard.

Do their North American buyers ever suffer pangs of conscience when they read about the horrible killings so often associated with the commerce that fuels their appetite for these illicit drugs? Or is their appetite for drugs simply out of control?

Americans can disagree about the effectiveness and the wisdom of the long-standing war on drugs, but while so much attention is being paid to the likes of Morales, we should also look at the consumers. Without them, these cartels would be out of business.